Music•PRO 9-15 earplugs from Etymotic Research use active adaptive electronics to gradually provide 9 or 15 dB (switchable) of sound reduction when needed, yet offer natural, unattenuated hearing for normal listening when sound levels are below the preset threshold. Full-fidelity sound reproduction is delivered via high-definition, balanced-armature drivers, high-sensitivity microphones and advanced signal processing with a 40 Hz to 16 kHz bandwidth. Retail is $399/pair, and there a large selection of ear tips is designed to fit the majority of ear types.